When SHIVA spurned her original advances, she decided to renounce the transient silliness of life and become an ascetic like him. A dark, somber figure, she ended up skulking in a forest in miserable mode.
This was not getting her very far. So BRAHMA decided to cheer her up. He transformed her into a dazzling blonde. And not just her hair. He turned her skin bright yellow.
No-one can be miserable for long with gleaming golden skin, so she bounded off to become a Goddess of Corn for a while before settling down to those morose austerities again. Everyone needs a vacation now and again.